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Offline BillyF

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billy's racer
« on: October 24, 2014, 02:06:44 PM »
hi folks just wanted to share with you my slow progress on my '48 racer (not a serious racer but to be road legal with daytime mot hopefully)
built up the wheels on 19" rims keeping the rear standard, but  found a 7" hub from something and managed to get it to fit the forks.
the lightweight 4 speed box has the same width lugs as the 3 speed, bent the rear down tube forward and repositioned the hole and it all fits nicely with the benefit of the 3 spring clutch so i can add more plates and slacken the springs to make it easier on the hand.
fitted a friction steering damper of a bigger bsa.
shortened the travel on the forks so the springs arnt slack on full droop.
i intend running it on 12 volts total loss so i made up a dummy dynamo out of 3"exhaust pipe and bits.
i am hoping to do a load of tuning things to the engine
i just took delivery of a new big end from alpha to fit to my lightened flywheels (i am hoping to take a load of photos).
this got me looking at the oil system, my intentions are to fit a brass stop valve in the feed, open up all the drillings, do away with the anti wet sumping bit, fettle the crank bush and generally make it easier for the oil to get to the big end.
i am going to fit a lip seal on the out side of the camshaft and raise the oil level in the cam chest by blocking the drain hole back to the crankcase and re drilling it higher up to hopefully help the cam and followers get better lubricated and that is about it up to now.
next - big valves, squish head, big carb,high ratio rockers, and get the compression up a bit

Online Cosmikdebriis

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Re: billy's racer
« Reply #1 on: October 24, 2014, 02:58:15 PM »
Good luck and make sure you keep us informed.

I once tried to convert a C15 to wet sump including the gear box to get a bit more oil in the system. Can'y honestly say I remember the end results but presumably they weren't disastrous or I would.

I'd also considered, but never tried, using an electric oil pump to add a bit of oomph. (though not considered it on a C).

Too much oil hanging about amongst the moving parts can considerably increase drag and in extreme cases, as Yamaha found out on the TX750, froth up with catastrophic results.

Raising compression is easy though I think you'll need a Colt (ally) head to avoid over heating, if you go far enough to make any real difference to performance.

An alternative would be to run on Ethanol which would keep things nice and cool.

Electronic ignition might be worth considering.

In my experience you may well need to beef up the clutch too ;)


A bike on the road... Is worth two in the shed...

Offline camman3

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Re: billy's racer
« Reply #2 on: October 24, 2014, 07:03:08 PM »
And don't forget you'll need to stop......so a better brake will help ;D
Good luck.
Graham
1957 C12
In sunny (sometimes) Christchurch, Dorset, UK

Offline BillyF

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Re: billy's racer
« Reply #3 on: October 31, 2014, 01:28:09 PM »
hi folks
has any of you ever worked out the balance factor for the c11. i have been messing about measuring mine as i have lightened the flywheels and it seemed to work out at about 45%, i checked a standard set of wheels and it came out much the same. seems very low, i thought 60 - 70% would have been more like it. any comments would be appeciated
cheers bill

Offline Lekkie

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Re: billy's racer
« Reply #4 on: October 31, 2014, 01:56:25 PM »
Quote
Raising compression is easy though I think you'll need a Colt (ally) head to avoid over heating, if you go far enough to make any real difference to performance.
And if you want to go down that route, it just so happens that there is one on ebay right now.
http://www.ebay.co.uk/itm/BSA-C11G-C12-ALLOY-CYLINDER-HEAD-ARIEL-COLT-2-/390961861311?pt=UK_Motorcycle_Parts_13&hash=item5b072492bf

Offline BillyF

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Re: billy's racer
« Reply #5 on: January 31, 2015, 03:09:27 PM »
hi folks
got my c11 "racer" painted and back together and running. my mate has a rolling road so we are going to put it on and run it up to see what it has got. there should be some photos attached
cheers bill

Offline BillyF

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Re: billy's racer
« Reply #6 on: January 31, 2015, 03:24:19 PM »
hi again
here is a brief spec. of the engine
flywheels lightened
balance factor changed to 60%
new alpha big end
rebored 60 thou
apex 3 piece oil control ring
total seal gapless second ring
solid copper head gasket 0.9mm
made up a cam based on the ramp type woth 102' lobe centres (gives 2mm lift at tdc)
fitted a c11g crank seal
opened out all the oil gallerys
raised the oil level in the cam chest
brazed up the combustion chamber to give some squish
fitted a 38mm inlet valve and 33mm exhaust with hardened insert
improved the crankcase breathing
fitted 1 1/16" carb with long air horn

some more photos

Offline Biker Grandad

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Re: billy's racer
« Reply #7 on: January 31, 2015, 03:37:21 PM »
Hi to all. That's a lovely bike, you did a good job. Bob.
(Biker Grandad) Too Old To Die Young  C12.b31
  from Southampton Hampshire. England.
  Torrevieja  Spain.

Offline camman3

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Re: billy's racer
« Reply #8 on: January 31, 2015, 04:35:14 PM »
Nice job Bill, I dont usually like to see them messed about with too much, but you have got the balance just right, and the quality of the work looks really good :)......no bell bottom trousers for pillion, I would suggest ;D
Graham
1957 C12
In sunny (sometimes) Christchurch, Dorset, UK

Online ianinglis

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Re: billy's racer
« Reply #9 on: January 31, 2015, 05:19:51 PM »
and mind your own bell bottoms on the end of the crankshaft ;D ;D ;D ;D


ian
BSA C10L 1956 - JFO 588
BSA C10L 1954 - MVE 107
RM6 RALEIGH RUNABOUT
ENFIELD DIESEL KUBOTA OC 95
BSA M21 RIGID RKN 816
CBF 1000
BSA ARIEL 3

Offline rogerwilko

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Re: billy's racer
« Reply #10 on: January 31, 2015, 09:48:20 PM »
Don't over rev it, the flywheels have a reputation of disintegrating!

Online MilitaryRon

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Re: billy's racer
« Reply #11 on: February 01, 2015, 07:16:34 AM »

I don't think that's a pillion seat. More like a lay down saddle for the rider. Ron

Offline BillyF

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Re: billy's racer
« Reply #12 on: February 01, 2015, 08:13:17 AM »
hi roger
i am interested in your comment about the flywheels and would like to know a bit more.
at what revs would you consider them to be unsafe
how many have you witnessed flying to pieces
has any body else found this to be the case because it is something to worry about
mind i would have thought that the rod or piston would be the first to let go
cheers bill

billfalconer.webs.com

Offline BillyF

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Re: billy's racer
« Reply #13 on: February 01, 2015, 08:22:49 AM »
as a p.s
i forgot to mention that i have taken a lot of metal from the diameter which should make it less likely to pull its self apart and if it does there should be a lot less metal to fly about (i am looking a 7000rpm which should give about 90 mph with its present gearing)
cheers again bill

Offline timsdad

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Re: billy's racer
« Reply #14 on: February 01, 2015, 09:07:20 AM »
That's an interesting project, Billy, and a neat, purposeful bike.

What have you done to improve its breathing? As you no doubt know, with reduced flywheels the oil will cling to the crank more, and cause problems, if there's pressure in there so it's usual to add an extra breather or two with one-way valves in rather than rely on a timed breather or BSA's little flappy thing.

Ray
Just a motorcyclist.